The self-declared "Democratic Socialist" is the only Democrat in the race other than Hillary Clinton.

Sanders admitted he may be fighting a losing battle.

"I am not here to tell you with 100 percent certainty that we can beat these guys, but what my campaign for president is about is to say we are not going to give up. We love this country too much to say that the billionaire class can have it all," said Sanders.

At an event in Concord, Sanders railed against the lopsided distribution of wealth across the nation.

"It is not sustainable. It is not what America is all about, and together, we have got to change that," said Sanders.

The senator also talked about making public colleges and universities free, providing universal healthcare and protecting the environment.

"He's addressing the issues, and he's the only one that's doing that right now, but the greater issue is how to do you translate all of that into action," said Stevia Lynch, of Merrimack, New Hampshire.

Sanders supporters said it will be tough to take on the notoriety and money of Clinton's campaign and wondered whether the former secretary of state is part of the problem.

"I have to say that Hillary has maybe been in the game too long at such a high level that she has lost touch with what it is to be us," said Jeanny Aldrich, of Chesterfield, New Hampshire.

Former New York Gov. George Pataki is expected to announce his intentions to run for the Republican nomination Thursday.